The present invention relates to a sensor for detecting rotational movement.
Conventionally, such a sensor is disclosed in GB 2061502 and GB 2154739, for example. In the conventional sensor for detecting rotational movement about an axis, a resonator which is in the form of a cup or cylinder is expected to be applied with radial vibrations by means of a pair of transducers. When the resonator rotates, the radial vibrations are detected by another pair of transducers for detecting rotational movement.
However, in the foregoing structure, the vibrations are along the radial direction of the resonator and the number of the points to which the vibrations are applied is two, by which the amplitude of the resonator is relatively small. Thus, due to a slight error of the resonator in rating such as length or radius and/or an asymmetry of the resonator about its axis which appears in an unevenness of weight or shape, the oscillation of the resonator becomes a non-uniform one, whereby a shift of nodes is generated. Thus, a null voltage becomes large, which results in that an improvement of the accuracy of the sensor is disturbed or prevented.